Retaining Wall and Home Stabilization
Cost of the project: $121,500
Project Start Date: August 2008
Project Finish Date: January 2009
Structural Engineer: Gervasio & Associates
Geotechnical Engineer: Copper State Engineering
Foundation repairs on the Gogte Residence are in full swing after identifying the construction errors (Part 1), defining the best design plan solution (Part 2) and overcoming the site challenges (Part 3). While this post uses all the industry lingo, we used photographs to better understand the work involved.
The carbon fiber reinforcing system used was a HJ3 carbon fiber 25 oz fabric. Stucco needed to be removed prior to application of the fabric. This was done with 7” knuckle and standard grinders. The fabric system produced 400 ksi of reinforcement in both vertical and horizontal directions per the grid pattern.
The helical piles were standard 2-7/8” round shafts with single 8” helixes and threaded connections. These were installed with 7000 lb torque drivers, powered with a manufactured hydraulic pump and where possible Kubota Min excavator. These piles produce a standard 62,000 lbs of bearing capacity. More than 5 times the weight of the house on them.
The micro piles chosen were Contech 30/16 mm bars. Carbide cross cut bits was used as the sacrificial bit. The 30mm is the outside dimension and 16MM is the inside hole size. These were manufactured by Titian Ischebeck. The equipment used to install the bars was a TEI 250 Drifter with a 360 degree universal skid steer attachment. This was powered by a custom made 30 GPM hydraulic pump and John Deere Skid Steer. The group pump used was a Whitman Conspray Grout pump. These tie backs were pull tested to more than double their required working loads by AZFS with oversight by the Engineering firms.
The permeation grouting was pumped with a small hydraulically powered piston grout pump. The grout casing was driven with both pneumatic and hydraulic hammers in both vertical and horizontal directions. Cellular foam was added to the grout mix to increase flow and decrease the weight of the grout from 150lbs per cubic foot to less than 50 lbs per cubic foot. This resulted in less overburden
With the home and retaining wall stabilized, we had to restore the preserve area to pristine condition, pass inspections by the consulting and engineering firms and recap the work completed …coming up in part 5 the final chapter.How can we help you? Leave a comment or ask us a question…we’re here to solve foundation problems.